Is CVE-2026-27586 actively exploited?

No active exploitation of CVE-2026-27586 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-27586 be exploited remotely?

Yes. CVE-2026-27586 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-27586?

CVE-2026-27586 has a CVSS score of 9.1 (CRITICAL) and an EPSS exploitation probability of 0.08%.

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CRITICAL

CVE-2026-27586

CWE-755Published: February 24, 2026· Updated: Feb 25, 2026

9.1

CVSS v3.1

EPSS:0.08%probability of exploitation in 30 daysPercentile:23.0th

Official Description

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in `ClientAuthentication.provision()` cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using `trusted_ca_cert_file` or `trusted_ca_certs_pem_files` for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.

NVD Source

Technical Analysis

CVE-2026-27586 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 9.1.